Rock drill



Sept. 8, 1925. 1,552,482 R. G. HANSON ROCK DRILL Filed Sept. 17, 1925 lam W7 Y Patented Sept. 8, 1925.

UNITED STATES RICHARD GREENWOOD HANSON, 0F STAFFORD, ENGLAND.

ROCK DRILL.

Application filed September 17, 1923; Serial No. 663,271.

To all whom it may concern:

Be it known that I, RICHARD GREENWOOD HANsoN, a subject of the King of Great Britain, and resident of Stafford, in the county of Stafford, England, have invented certain new and useful Improvements in and Relating to Rock Drills, of which the following is a specification.

This invention relates to rock drills. In existing devices of this character the drill. carrying head is fed mechanically towards the work and withdrawn at the same speed and by the same means.

According tothe present invention the head is capable of being withdrawn from the work at a greater speed than that at which it is fed forward.

The invention may therefore be said to consist broadly of a rock drill comprising means whereby the head may be quickly withdrawn from the work.

In practice this may be effected by providing means such as a split nut associated with the feed mechanism whereby the head may be temporarily disconnected from such feed mechanism so as to permit the head to be withdrawn from the work rapidly by hand.

In order that the invention may be clearly understood an embodiment of the same will now be described by aid of the accompanying drawings in which Figure 1 is a fragmentary longitudinal section through the head of a rock drill according to this embodiment of the invention.

Figure 2 is a transverse section of the same taken through the centre of the split nut.

According to the embodiment of the invention illustrated in the drawings the food mechanism comprises a load screw a, which is rotated by a motor, gearing or other means not shown, and a split nut 72 carried by the movable head 0, the two portions of which nut tend to become separated and out of engagement with the lead screw by spring means so that the head is free to be moved quickly by hand.

In this embodiment of the invention the two portions of the split nut are adapted to be forced together by means of a cam 03 having two dimensions. This cam is rotatably mounted upon one side of the movable head and provided with a handle 6 to enable it to be operated.

The two halves of the split nut are slidably mounted upon a pair of guide pins f the upper ends of which carry a saddle piece g which rests upon the uppermost surface of the cam. The sides of the cam thus bear against the under-side of this saddle piece and the top surface of the upper half of the split nut.

Thus when the cam is turned so that its smaller dimension opposes this saddle piece and the nut respectively the two halves of the nut are free to be forced apart by the aforementioned spring means so as to dis connect the head of the drill from the lead screw. Upon imparting a quarter turn to the cam the two halves of the nut are forced together thus locking the drill head to the lead screw.

The spring means aforementioned may conveniently consist of a pair of helical springs h disposed in pockets 2' in the two halves of the nut and surrounding the two guide pins f.

This invention is particularly applicable to rock drills embodying the now well known wave transmission principles in which the percussion hammer of the drill is oscillated by means of pressure waves produced in a line containing liquid by a suitable generator.

What I claim and desire to secure by Letters Patent is In a rock drill, in combination, a movable head, a lead screw, a split nut engaging said movable head and said lead screw, the two halves of the split nut having pockets, springs in said pockets adapted normally to hold said halves apart, guide pins upon which the two halves of the nut are slidably mounted, a saddle piece carried by the up per ends of said guide pins, and a cam located between the nut and said saddle piece, and all arranged so that when the cam is turned to oppose its smaller dimension to the saddle piece and the nut respectively the two halves of the nut will be forced ICHA D GR ENWOOD HA Q 

